Licht-und elektronenmikroskopische Untersuchungen an Desmidiaceen

Ohne ZusammenfassungMit 42 Textabbildungen.     

Der Bestand vonCalanus finmarchicus in der Irminger See im Juni 1955

Zusammenfassung 1. Von den drei morphologisch unterschiedenen und zuweilen als Arten voneinander getrennten Formen des CopepodenCalanus finmarchicus s. 1. tritthelgolandicus (Claus) nur im Südosten des Untersuchungsgebietes im Nordostatlantischen Wasser auf,glacialis Yashnov ist auf das Ostgrönland-Wasser jenseits der Polarfront beschränkt, kommt aber vereinzelt auch im Tiefenwasser der Irminger See vor, währendfinmarchicus (Gunnerus) s. str. über das ganze Gebiet verbreitet ist und im Irminger-See-Wasser und dem angrenzenden Mischwasser reine Bestände bildet.2. Das Vorkommen intermediärer Formen in den Grenzgebieten sowie die großen, sich teilweise überlagernden Variationsbreiten der Merkmale lassen vermuten, daß die genannten Formen genetisch nicht streng isoliert, sondern als geographische Rassen einer plastischen ArtC. finmarchicus s. l. miteinander verbunden sind.3. Der Bestand derfinmarchicus-Rasse ist in mehrere Populationen aufgeteilt, die sich in ihrer mittleren Körpergröße und dem Entwicklungsgrad unterscheiden. Ihre Verbreitungsareale entsprechen weitgehend der hydrographischen Gliederung der Wasserkörper.4. In den Gebieten diesseits der Polarfront mit großen jahreszeitlichen Schwankungen der Temperatur besteht eine negative Korrelation zwischen der Länge der ausgewachsenen und auch jüngeren Stadien einerseits, und den örtlichen Temperaturverhältnissen andererseits. Derartige Beziehungen fehlen dagegen in den Gebieten jenseits der Polarfront mit kleiner Jahresamplitude der Temperaturschwankungen. Tiere, die durch Verdriftung oder Vermischungsvorgänge unter andere Milieuverhältnisse geraten, behalten ihr ursprüngliches Längenwachstum bei.5. Dieses unterschiedliche Verhalten gegenüber der Temperatur macht es wahrscheinlich, daß beiCalanus finmarchicus das Längenwachstum zu einem sehr frühen Zeitpunkt der Entwicklung im wesentlichen determiniert wird.

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The stock ofCalanus finmarchicus in the Irminger Sea in June 1955

During the cruise of the Fisheries Research vessel Anton Dohrn in the Irminger Sea in June 1955, the morphological and physiological composition of the stock of the copepodCalanus finmarchicus (Gunnerus) sensu lato was studied. The formhelgolandicus is restricted to the Northeast Atlantic water body, the formglacialis to the East Greenland water body, whereasfinmarchicus sensu stricto is distributed throughout the whole area. In regard to the wide variation ranges of the morphological distinctive traits and to the occurrence of intermediate forms in the border districts, the forms, hitherto described as species, are regarded as geographical races. The stock ofC. finmarchicus s. str. is divided into several populations, which differ one from another in their medium size. InC. finmarchicus, the size of adults and earlier stages is negatively related to the temperature; this correlation is lacking in populations which drifted under different temperature conditions. The distribution of the forms and populations correspond to the hydrographical and planktological pattern.

     

A comparison of sperm morphology and silver nitrate staining characteristics in the domestic ferret and the black-footed ferret

Ejaculated sperm from the domestic ferret (Mustela putorius furo) and the black-footed ferret (Mustela nigripes) were compared for differences in morphological abnormalities and argentophilic protein distribution. Thawed domestic ferret sperm was also compared to fresh sperm to determine whether there were any effects on cell morphology due to cryopreservation. There were statistically significant differences between the two species of ferret in two of the categories scored. The domestic ferret had a higher frequency of cells that were bent in the midpiece and in the principal piece, and a higher frequency of headless and tailless cells when compared to the black-footed ferret. There were no statistically significant differences in cell morphology between the fresh and cryopreserved ejaculates of the domestic ferret employing a standard egg yolk cryoextender. Silver nitrate staining distribution was different between the two species in both the head and tail region.     

Evidence for the Presence of Chlorophyllide b in the Green Alga Scenedesmus obliquus in vivo

Chlorophyllide b could be extracted from the wild type of Scenedesmus obliquus and its pigment mutant C-2A'. Its identity was proved by absorption and fluorescence spectroscopy and by a positive hydroxylamine test. Chlorophyllide b could be transformed into pheophorbide b and methylpheophorbide b. The formation of chlorophyllide b from chlorophyll b by dephytylation with chlorophyllase could be ruled out. The stimulation of chlorophyllide b biosynthesis with o-phenanthroline, as described in the literature, could not be confirmed under physiological conditions.     

Fermentation of potato mash,potato mash/maltrin mixtures,maltrin and wheat starch usingZymomonas mobilis

Summary Potato mash, potato mash/maltrin mixtures, maltrin and wheat starch have been fermented with 95 to 98% conversion efficiencies. Highest ethanol yields obtained were 13.5% (v/v) in 24 h. The addition of 20% backset (= thin stillage) or change of pre-culture conditions did not affect the process.

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Fermentation de purée de pommes de terre seule et en mélange avec la maltrine, de maltrine seule et d'amidon de froment par Zymomonas mobilis

Résumé On fermente la purée de pommes de terre seule et en mélange avec la maltrine ainsi que l'amidon de froment jusqu'à 95 à 98% d'efficacité de conversion. Les rendements les plus élevés en éthanol sont de 13.5% (v/v) en 24 h. Le recyclage de 20% de résidu fluide de fermentation ou le changement des conditions de préculture n'affectent pas le processus.

     

Identification of a widely distributed 90-kDa glycoprotein that is homologous to the Hermes-1 human lymphocyte homing receptor

Homing of recirculating lymphocytes from the blood into the lymphoid tissues is mediated by 90-kDa homing receptors on the lymphocyte cell surface, allowing selective binding to specialized endothelium lining high endothelial venules. This study describes two novel mAb, NKI-P1 and NKI-P2, directed against functional epitopes of a human lymphocyte homing receptor, gp90. Biochemical studies demonstrated that these antibodies recognize a 90-kDa glycoprotein which is similar to the Ag recognized by the mAb Hermes-1. This notion was confirmed by immunohistochemical studies showing identical reaction patterns. Furthermore, it was observed that NKI-P1 and NKI-P2 blocked adhesion of lymphocytes to high endothelial venules. Immunohistochemical, immunofluorescence, and immunoprecipitation studies revealed that gp90 is widely expressed on hemopoietic cells including lymphocytes, macrophages/dendritic cells, myeloid cells, and erythrocytes. The gp90 is also expressed on a number of nonhemopoietic cells such as endothelial cells, certain epithelial cells, and fibroblasts. In addition to its expression on normal cells, gp90 is present on a spectrum of tumor cell lines of lymphoid, monocytic, epithelial, glial, and melanocytic origin. In addition to the 90-kDa product, the antibodies immunoprecipitate several polypeptides in the range of 120 to 200 kDa. Interestingly, it was observed that certain mamma tumor cell-line cells lack the 90-kDa polypeptide indicating the heterogeneous expression of the molecules recognized by the antibodies. These results indicate that the 90-kDa glycoprotein homologues of the Hermes-1 human lymphocyte homing receptor are expressed on hemopoietic tissues as well as on a number of nonhemopoietic tissues and tumor cell lines. Although the function of these molecules in nonlymphoid cells is presently unknown, they might play a role in cell-cell or cell-matrix adhesion.     

Electron spin resonance evidence for the formation of free radicals in plants exposed to ozone

Electron spin resonance (ESR) spectroscopy was used to demonstrate that free radicals are formed in O₃-fumigated plant leaves prior to the formation of visible leaf injury. ESR signals with a g-value of 2.0037 to 2.0043, were observed in pea ( Pisum sativum L. cv. Feltham first) and bean ( Phaseolus vulgaris L. cv. Pinto) plants that had been fumigated for 4 h with 70–300 nl l⁻¹ of ozone after they had been treated with the spin-trap N- t -butyl-α-phenylnitrone (PBN). The size of the ESR signals increased with the concentration of ozone used but the nature of the trapped radicals could not be identified. However, further experiments using an inhibitor of ethylene biosynthesis, arninoethoxyvinyl glycine (AVG), showed that the reaction between ozone and ethylene is the cause for ozone toxicity.     

Mechanical impedance increases aluminium tolerance of soybean (Glycine max) roots

The effect of aluminium (Al) on root elongation was studied in solution culture and sand culture. Compared to solution culture, in sand culture a ten times higher Al supply was necessary to inhibit root elongation to a comparable degree. This was due to a much lower Al uptake into the 5 mm root tips in sand culture. Fe concentrations in root tips were also lower in sand culture. Ca concentrations were higher and less depressed by Al, whereas Mg and K concentrations were not affected by the culture substrate. Regressions of Al concentrations in root tips versus inhibition of root elongation by Al revealed root damage at lower Al concentrations in sand culture. The effect of culture substrate on Al tolerance was independent of N source and could also be shown in flowing solution culture with and without sand. The results indicate that mechanical impedance in sand culture decreased Al uptake. This may be due to enhanced exudation of organic complexors thus reducing activites of monomeric Al species.